On Estimating the Effectiveness of Temporal and Spatial Coherence in Parallel Ray Tracing
Biagio Cosenza, Gennaro Cordasco, Rosario De Chiara, Ugo Erra, Vittorio Scarano · CINECA IRIS Institutional Research Information System (University of Basilicata) · 2008
In this paper we estimate the effectiveness of exploiting coherence in Parallel Ray Tracing. We present a load- balancing technique which divides the original rendering problem in balanced subtasks and distribute them to independent processors through a Prediction Binary Tree (PBT). Furthermore the PBT allows to exploit temporal coherence among successive image frames. At each new frame, it updates the current PBT using a cost function which uses the previous rendering time as cost estimate. We also provide two heuristics which take advantage of data-locality. We assess the effectiveness of the proposed solution by running two experiments. The £rst one aims to investigate the accurancy of predictions made using the PBT. Results show that such predictions are quite accurate even considering a heavily unbalanced scene and a fast moving camera. The second experiment evaluates the two locality-aware heuristics showing a modest improvement.